Cut stems, remove damaged parts. Wash and drain. Heat a large saucepan without any fat. When hot, throw spinach in and cook until it loses its vegetation water and reduce in volume. Remove water that appeared while cooking.
While spinach are cooking, peel garlic cloves. Cut them in half and remove germs. Then cut into thin strips. Heat olive oil in a frying pan (be generous) and fry garlic slices.
When garlic turns brown, pour them, with the olive oil, in the sauce pan containing spinach and heat for a few minutes to warm spinach and let them absorb roasted garlic flavors.